What do you mean by "fiat price"?There's no such term as fiat price.There's only fiat money.
Do you mean the USD/EUR price of bitcoin?
Anyway,the so called "stable coins" is sooner or later disappear and their creators will cashout a lot of money.
Their fiat reserves(if they really have such reserves) are going to decrease a lot,because everyone will be buying btc and altcoins.